The invention relates to a control device in a motor vehicle having an electronically controllable automatic transmission depending on the position of an electronic transmission selector lever.
A control device of such a type, in particular in the form of a safety device, is known from DE 102 53 936 A1, for example.
For electronically controlled automatic transmissions a large number of safety measures need to be provided to counter unintentional rolling-away of the vehicle. A safety measure of such a type is described, for example, in the “Key Interlock” specification (according to FMVSS 114) which has long been known. This specification states, inter alia, that in vehicles having an automatic transmission, the ignition key may only be withdrawn when the selector lever of the automatic transmission is located in the “P” position for parking. By this means, the situation is intended to be prevented where the driver exits the motor vehicle without having previously secured the motor vehicle against unintentional rolling-away. In order to satisfy this specification, the ignition lock may exhibit suitable mechanical locking mechanisms which can be actuated via the ignition key.
Increasingly, however, motor-vehicle access systems and startup systems without a mechanical ignition lock are finding application. Such keyless startup systems without a mechanical ignition lock include an identification transmitter (ID transmitter—a key with integrated transponder) to be carried by the user of the vehicle, as well as a device for starting and stopping the engine, which can be actuated manually by means of a push-button or even automatically by means of an appropriate electronic drive-control unit (MSA, automatic engine start/stop). As soon as the ID transmitter is detected in the passenger compartment of the vehicle, the authentication of the ID transmitter is carried out via an interrogation-and-response dialog of the ID transmitter with a transceiver device of the motor vehicle, and in the case of positive authentication the engine is started after actuation of the device.
The latest developments are proceeding in the direction that for the purpose of starting the engine the ID transmitter no longer even has to be inserted into the socket, but rather the electronics located within the motor vehicle, regardless of whether the ID transmitter is located in the socket, establish the presence of the ID transmitter within the vehicle and carries out the requisite authentication. The corresponding new developments are known under the designations “Comfort Access” and “Keyless Go”.
In connection with these new systems, from DE 102 53 936 A1, for example, a solution is demonstrated as to how the key-interlock specification can be satisfied in the use case of keyless startup systems in which the ID transmitters are located at an arbitrary position in the motor vehicle without a predetermined physical connection to other parts of the motor vehicle. In this case, there is provision to be able to shut down the engine also while the vehicle is in motion, provided that the speed of the motor vehicle is greater than a certain threshold speed. Below the threshold speed, the vehicle firstly has to be brought to a standstill, and the parking position “P” has to be engaged before the engine can be shut down.
In more recent vehicles, however, in particular having an electronic transmission selector lever, a shutdown of the engine can also be made possible irrespective of the chosen transmission position and irrespective of the speed of the vehicle if certain other defined conditions have been fulfilled; in particular if certain engine-shutdown conditions within the scope of an automatic engine start/stop device (MSA) are present.
In DE 102 53 936 A1 it is already proposed that a motor vehicle having an automatic transmission is to be moved while in transmission position “N” (for “neutral”) with the engine switched off. Two possibilities for this arise as described below.
In a first alternative, the ID transmitter has not been inserted into a vehicle-side socket and is accordingly located, for example, in a pocket of the driver. The driver engages transmission position “P” for parking, switches the engine and the ignition off, switches the ignition on again, and engages (where appropriate with simultaneous actuation of the brake) transmission position “N” for neutral. The motor vehicle can now, for example, be pushed by hand or pass through a car wash. For the purpose of driving away out of the car wash, however, the footbrake has to be applied for a restart of the engine, in order to be able to switch from position “N” to position “D” for Drive.
In a second alternative, the ID transmitter is inserted into the motor-vehicle-side socket provided for it and is locked therein, as known from the prior art. As a consequence of this, the engine and the ignition can be switched off at any time and in any selector-lever or transmission position. In the normal case, the engine is accordingly shut down in position “D” for “Drive”, and subsequently position “N” is engaged. Here too, the motor vehicle can now, for example, be moved manually or pass through a car wash.
It is an object of the invention to simplify the handling of a motor vehicle having an automatic transmission, in particular with regard to exiting a car wash.
This and other objects are achieved by the control device according to the invention for a motor vehicle. The control device has an electronically controllable automatic transmission, an electronic transmission selector lever and an electronic control unit. The control unit, which is preferably the transmission control unit, has a car-wash functional module such that, after activation of the car-wash functional module, at least once and/or at least for a predetermined limited time, the following actions are permitted, in each instance without actuation of the brake pedal:
a shutdown of the engine in transmission-selector-lever position “N”,
a subsequent restart of the engine in transmission-selector-lever position “N” and also
a change from transmission-selector-lever position “N” to “D”.
The car-wash functional module can preferably be activated or deactivated arbitrarily by the driver via an operating element of the display. In this case, for example, a menu item may be provided for selection of a permanent activation, and/or a menu item may be provided for selection of only a single activation, and/or a menu item may be provided for selection of a temporally limited activation of the car-wash function.
Alternatively or additionally, the car-wash functional module can be activated automatically by a change from automatic gear selection “D” to position “N,” and by subsequent manual shutdown of the engine.
Still further defined signal sequences for activating the car-wash function may also be provided.
In an advantageous further development of the invention, a monitoring device monitors for the presence of the driver. The transmission parking lock assigned to transmission-selector-lever position “P” is engaged automatically if no presence of the driver is detected.
The invention relates, in particular, to vehicles having automatic transmissions which travel through a car wash with a pull-cable, in which the vehicle is pulled along in a rolling manner. But the car-wash function may, of course, also be employed for other, similar situations.
According to the prior art, the driver ordinarily has to actuate the brake twice at the end of the car wash, in order to be able to drive the vehicle out of the car wash. The first actuation of the brake is required in order to start the internal combustion engine. The second actuation of the brake is required shortly after this, in order to change from automatic gear selection “N” to automatic gear selection “D”.
In the case of vehicles following one another in close succession in the car wash, there is a risk of tailgating situations or collisions with one's own vehicle occurring by reason of an excessively long actuation of the brake.
If the footbrake is not applied sufficiently strongly or for a sufficiently long time during the restart of the engine, automatic gear selection “P” is engaged, whereupon the transmission lock becomes active and the pull-cable roller of the car wash may extend underneath the stationary vehicle, unless an emergency-stop function has been implemented in the installation.
Irrespective of both risks, this drive-out process represents a fundamental stress situation for the driver.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.